Positive photoresist compositions comprising an alkali soluble resin and a quinonediazide ester are excellent in definition, sensitivity and etching resistance and hence have been satisfactorily used for the production of semiconductor devices and liquid crystal devices.
In the current manufacture of ultralarge-scale integrated circuit (ultra LSI), a high definition of not more than half a micron, for example, of 0.4 .mu.m, 0.35 .mu.m or the like is required. In addition, there are demands on photoresist compositions which can form a resist pattern satisfactory in definition, exposure margin, focal depth range properties and having a good sectional shape.
It is, however, difficult to form a resist pattern having an excellent sectional shape in the formation of a fine pattern of half a micron or thinner. With a pattern becoming finer, the rate of change of the pattern shape due to exposure change increases (i.e., the exposure margin is small), and thus, a little difference in exposure conditions invites a large difference in pattern shape. Therefore, the exposure with the use of any of conventional photoresist compositions must be controlled within a very narrow range in order to obtain a good pattern shape of the exact size of a mask pattern.
It is, therefore, an object of the present invention to provide a positive photoresist composition having a high definition, a high sensitivity and a large exposure margin, and to provide a novel polyphenol compound and a quinonediazide ester thereof which can be constituents of the composition.